In general, the manufacture of hollow glass items, for example such as bottles, must meet various constraints, and in particular shape constraints, for example the position of the neck, manufacturing tooling constraints, for example for stripping, constraints related to the distribution and weight of the glass, and specific constraints related to packaging.
One known method for manufacturing this type of item consists of introducing at least one molten glass parison into a parison mold at a predetermined temperature and preforming the article in the parison mold from said at least one parison by injecting a pressurized gas, for example such as air, into the parison mold.
The blank of the item thus produced is transferred into a finishing mold and the item is definitively formed in that finishing mold by also injecting a pressurized gas.
Until now, hollow glass items, and more particularly bottles intended for perfume and cosmetics, have been made with thick glass distributions, which is considered very qualitative and contributes to conveying an image of luxury. However, the trend is to produce hollow glass items with practically invisible glass walls so as to convey an image of lightness, refinement, elegance and apparent fragility.
To obtain this output on a hollow glass item that can be industrialized, several conditions must be met, i.e.:                very thin glass thicknesses,        the most regular possible distributions of glass to avoid disrupting the perception of the eye, and        a sufficient mechanical strength for handling of the item.        
With the aforementioned method, the adjustment of the parison mold and the geometry of the blank make it possible to obtain glass walls with a thin and regular thickness, but excess glass remains in the bottom of the item, centered on the axis of said item.
This excess forms a curved overthickness inside the item that specialists call a “marloquette” or a “police hat”. This excess thickness disrupts the regularity of the distribution of the glass.
Furthermore, in light of the small thickness of the walls of the item, the distribution stresses of the glass impose a much higher manufacturing rhythm than those currently used for items having thicker walls. A gaseous interface forms between the blank and the walls of the finishing mold and is imprisoned during the blowing phase. This interface cannot escape due to a very small amount of time, thereby causing a deformation of the main faces of the item.
The invention aims to propose a method and equipment for manufacturing a thin, hollow glass item that avoids these drawbacks.
The invention therefore relates to a method for manufacturing a hollow glass item having thin walls and a thin bottom, said method comprising:                feeding at least one molten-glass parison into a parison mold,        forming, in the parison mold, a blank of the item from said at least one parison,        transferring the blank of the item into a finishing mold,        forming the item in the finishing mold,characterized in that, while forming the item in the finishing mold, excess glass is directed out of the bottom of the item so as to form a convex bulge, and the bulge is removed such that the thickness of the bottom of the item is substantially constant.        
According to other features of the invention:                during forming of the item in the finishing mold, the gas forming between the main faces of the walls of the item and the inner walls of said finishing mold is channeled toward the outside of said finishing mold, and        the outer bulge is eliminated from the bottom of the item by at least one cutting operation followed by at least one polishing operation of the outer face of the bottom of the item.        